Individual study: Augmenting small populations of plovers: an assessment of cross-fostering and captive-rearing
Powell A.N. & Cuthbert F.J. (1993) Augmenting small populations of plovers: an assessment of cross-fostering and captive-rearing. Conservation Biology, 7, 160-168
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Foster eggs or chicks of waders with wild non-conspecifics (cross-fostering)
A replicated and controlled experiment on two islands in Lake Michigan, USA, in 1987-9 (Powell & Cuthbert 1993) found that killdeer Charadrius vociferus eggs incubated and raised by spotted sandpipers Actitis macularia did not have significantly different hatching or fledging rates, compared to parent-reared eggs and chicks (47% hatching success, 0.8 fledglings/pair and 48% fledging success for cross-fostered chicks, n = 16 broods vs. 54%, 0.6 fledglings/pair and 27% for parent-reared chicks, n = 24 broods). There were no significant behavioural differences between parent-reared and cross-fostered chicks and one cross-fostered chick was seen two years after fledging, when it courted and mated with wild killdeer. No parent-reared chicks were seen again but the authors note that killdeer have low site-fidelity and so may not be seen again.
Artificially incubate and hand-rear waders in captivity
A replicated and controlled experiment on two islands in Lake Michigan, USA, in 1989 (Powell & Cuthbert 1993) found that artificially incubated killdeer Charadrius vociferus eggs had significantly higher hatching and fledging success than either wild-reared or cross-fostered (raised by spotted sandpipers Actitis macularia) eggs and chicks (82% hatching success, 2.3 fledglings/pair and 78% fledging success for captive-reared chicks from six broods vs. 47%, 0.8 fledglings/pair and 48% for cross-fostered chicks from 16 broods, and 54%, 0.6 fledglings/pair and 27% for parent-reared chicks for 24 broods). Eggs were removed during the first week of incubation where possible and incubated at 39oc, transferred to a 35oC box and then released into outdoor pens. Killdeer chicks are precoccial and so fed themselves from tubifex worms, mealworms, earthworms and cat food spread in water over sand (to simulate natural feeding conditions). They also fed on insects attracted to heat lamps. Chicks were released into the wild at 35 days-old and no behavioural differences were observed after release. No parent-reared chicks were seen in following years, whereas one captive-reared chick was seen the next year.